Imaging system having a rotatable image-directing device

ABSTRACT

An image acquisition system for capturing images of a scene is provided. The system includes a stationary image acquisition device that receives optical images. A light-directing device directs images toward the image acquisition device. The light-directing device pivots about a pivot axis over a scan range that is less than 360 degrees.

The present application is based on and claims the benefit of U.S.Provisional Patent Application Ser. No. 60/857,905, filed on Nov. 9,2006, the content of which is hereby incorporated by reference in itsentirety.

BACKGROUND

The present disclosure relates generally to imaging systems, and morespecifically, but not by limitation, to imaging systems configured toacquire image data of a wide area scene.

There are known imaging systems for capturing image data of a wide areascene (e.g., image data of a panoramic scene having a wide field-of-view(FOV)). There are also imaging systems that are configured to acquiremultiple image frames of a wide area scene and utilize the multipleframes to construct a digital representation of the wide area scene.Further, some of these conventional systems employ a rotating mirror toreflect images to a camera. Unfortunately, these conventional systemscommonly require complex hardware and software components to acquire andprocess the captured images. Many of these conventional systems have alow spatial resolution and significant image distortion. Further, therotating mirror mechanisms employed by conventional systems skew anddistort the reflected images. For instance, these conventional systemsemploy a mirror orientation that causes the reflected images to rotateon a lens of the camera.

For at least these reasons, there is a need for an image acquisitionsystem that collects video data at a high rate, at a high spatialresolution, and without image distortion commonly seen with conventionalsystems.

The discussion above is merely provided for general backgroundinformation and is not intended to be used as an aid in determining thescope of the claimed subject matter.

SUMMARY

An image acquisition system for capturing images of a scene is provided.The system includes a stationary image acquisition device that receivesoptical images. A light-directing device directs images toward the imageacquisition device. The light-directing device pivots about a pivot axisover a scan range that is less than 360 degrees.

These and various other features and advantages will be apparent from areading of the following Detailed Description. This Summary is notintended to identify key features or essential features of the claimedsubject matter, nor is it intended to be used as an aid in determiningthe scope of the claimed subject matter. The claimed subject matter isnot limited to implementations that solve any or all disadvantages notedin the background.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an image acquisition system,under one embodiment.

FIG. 2 is a schematic diagram illustrating an image acquisitioncomponent, under one embodiment.

FIGS. 3 and 4 illustrate image acquisition systems configured to performa one-dimensional (1-D) scan to acquire images of a scene.

FIG. 5 illustrates an image acquisition system configured to perform atwo-dimensional (2-D) scan to acquire images of a scene.

FIGS. 6 and 7 illustrate image acquisition systems configured to acquireimages of a scene utilizing a plurality of image directing devices.

FIG. 8 is a schematic diagram of an embodiment of an image acquisitionsystem including an illuminator.

FIG. 9 is a schematic diagram of a processing component configured toprocess image data, under one embodiment.

FIG. 10 is a schematic diagram of a display component configured todisplay image data, under one embodiment.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of a system 100 for acquiring andprocessing image data, including displaying, storing, and/ortransmitting the image data. System 100 includes an image acquisitioncomponent 102 configured to receive an optical image and generate adigital representation of the optical image. In one embodiment, imageacquisition component 102 is a camera configured to acquire images suchas still images and/or video. Data acquired by image acquisitioncomponent 102 can be provided in any suitable image format including,but not limited to, raw binary, AAF, 3GP, GIF, Animated GIF, ASF, AVI,MPEG (i.e., MPEG-1, MPEG-2, MPEG-3, MPEG-4), AVCHD (Advanced VideoCodecs High Definition), DSH, FLV, MOV, WMV, JPG, GIF, TIFF, PNG, BMP,to name a few.

Image acquisition component 102 is configured to capture image data overa wide spatial area (i.e., a substantially wide field-of-view). In thismanner, image acquisition component 102 can acquire image data of apanoramic scene, such as a landscape. In one embodiment, imageacquisition component 102 is stationary with respect to the surroundinglandscape and includes a rotatable image-directing device, such as amirror and/or a prism. In another embodiment, image acquisitioncomponent 102 includes a camera that pans (i.e., rotates) fromside-to-side while acquiring video and/or a series of still images. Inanother example, image acquisition component 102 includes a wide-anglelens to capture panoramic image data. Although not illustrated in FIG.1, image acquisition component 102 can include additional mediaacquisition components, such as a microphone.

The image data acquired by image acquisition component 102 is providedto a processing component 104 configured to perform processingoperations such as image processing, image target tracking, image changedetection, etc. Processing component 104 is configured to collect theimage data and associate, with the acquired image data, information suchas a time stamp indicative of when the image data was acquired and/or alocation identifier indicative of a spatial position of the acquiredimage data. For example, in the case where a plurality of images framesare acquired over a wide area scene, the processing component 104 canassign information to each acquired frame indicative of the spatialposition of the frame within the wide area scene.

Further, processing component 104 is configured to receive a pluralityof frames of image data and perform image data processing to arrange theplurality of frames. In one embodiment, processing component 104performs “autostitch” processing in which a plurality of frames ofacquired imaged data are arranged side-by-side to form a wide areaimage. Further, spatial position information associated with each frame(e.g., information indicative of the location of the particular framewithin the wide area image) can be utilized to arrange the plurality offrames together to form the wide area image.

Raw (i.e., unprocessed data) and/or processed image data can be providedto a storage component 106. Storage component 106 is configured toarchive image data for storage and/or subsequent retrieval. For example,the image data can be compressed to reduce the required memory forstoring and/or transmitting the image data. Processing component 104 canfurther be configured to retrieve stored data from storage component106.

In the illustrated embodiment, processing component 104 is furtherconfigured to provide image data to a display component 108. Displaycomponent 108 includes a visual display device, such as a monitor, forvisually rendering the image data. In one embodiment, display component108 includes an array of monitors configured to simultaneously display aplurality of frames of image data acquired by image acquisitioncomponent 102. Display component 108 receives the acquired image dataand visually renders the image data. As discussed above, spatialinformation relating to a position of the frame(s) of image data can beprovided and can be utilized to visually render the image data.

FIG. 2 is a schematic diagram illustrating one embodiment of imageacquisition component 102. In the illustrated embodiment, a camera 204is provided and is configured to receive an optical image 212 of a scene210 along an optical axis 213. It is noted that herein “optical axis” isutilized to refer to an optical image path along which camera 204receives image data. The optical axis can be perpendicular to, oralternatively at an angle with respect to, a lens of camera 204.Further, camera 204 is configured to acquire optical images centeredalong optical axis 213, as well as optical images that are at an anglewith respect to optical axis 213. In other words, camera 204 has afield-of-view, wherein light is accepted at all angles with thefield-of-view.

Camera 204 can be any suitable image acquisition device. In oneembodiment, camera 204 is configured to acquire images at a rate of 60frames-per-second (fps). In other embodiments, camera 204 can acquiremore than, or less than, 60 fps. For example, camera 204 can beconfigured to operate at 200 fps.

As illustrated in FIG. 2, image acquisition component 102 is configuredto acquire a plurality of frames 246 of image data from scene 210. Inthe illustrated embodiment, camera 204 is mounted in a stationary, orsubstantially stationary, position with respect to scene 210. To acquirethe plurality of image frames 246 of scene 210, an image-directingdevice 208 is provided for directing an optical image 212 to camera 204along an optical image path 214. In the embodiment illustrated in FIG.2, the image directing device 208 includes a single scan mirror 209configured to pivot about a pivot axis (not shown in FIG. 2). However,it is noted that in other embodiments image-directing device 208 caninclude a plurality of mirrors. For example, the image-directing device208 can include a plurality of scan mirrors 209 configured to pivotabout one or more pivot axes. Further, the image-directing device 208can also include one or more stationary mirrors for directing images tocamera 204.

Camera 204 collects light energy reflected by light-directing device 208along optical image path 214. Herein, the term “light”, or “lightenergy”, is utilized to refer to, in addition to “visible light”,electromagnetic radiation having wavelengths less than or greater than“visible light.” For example, the term “light”, or “light energy”, canrefer to infrared or near-infrared radiation, ultra-violet radiation,among others. In one embodiment image acquisition component 102 includesa multispectral and/or a hyperspectral imaging camera configured tosimultaneously acquire images at multiple wavelengths.

At a particular angular position of scan mirror 209, camera 204 receivesimage data from a frame 246 of scene 210 and has a field-of-view (FOV)244 at a standoff range 242. In one embodiment, FOV 244 of camera 204 isapproximately one (1) degree with respect to the pivot axis of scanmirror 208. However, camera 204 and scan mirror 209 can have anysuitable FOV 244. For instance, FOV 244 can be less than, or greaterthan, one degree depending on the desired application of imageacquisition component 102. A suitable FOV 244 can be 0.3-10 degrees, forexample. Further, in one embodiment standoff range 242 is approximatelyfour (4) miles in length. However, standoff range 242 can be anysuitable distance. For instance, standoff range 242 can be less than, orgreater than, four miles depending on the desired application of imageacquisition component 102.

Pivoting of scan mirror 209 enables camera 204 to acquire image datafrom each of the plurality of frames 246 over a scan range 240. In oneembodiment, scan range 240 is approximately eighty (80) degrees (withrespect to the pivot axis of scan mirror 208). In one particularexample, scan range 240 corresponds to a spatial width of scene 210 ofapproximately 7 miles. In other embodiments, scan range 240 can begreater than, or less than, 80 degrees. By acquiring each of frames 246using scan mirror 209, camera 204 can acquire image data of scene 210having a relatively high spatial resolution (i.e., “zoomed in”). In oneembodiment, camera 204 has a ground sampling distance (GSD) ofapproximately six (6) inches at a standoff range 242 of three (3) miles.

To enable scan mirror 209 to pivot over scan range 240, an actuator 222is operably coupled to electronics controller 220 and scan mirror 209,and is configured to step scan mirror 209 through scan range 240 betweeneach of a plurality of angular positions in response to a signal fromcontroller 220. Actuator 222 is configured to pivot scan mirror 209through scan range 240 in successive and repeating cycles. Asillustrated, a complete “scan” of mirror 209 can obtain a total of “N”image frames 246. In one embodiment, scan mirror 209 “steps” throughscene 210 to acquire 80 (i.e., “N”=80) frames. However, any number offrames “N” can be acquired. As will be discussed below, in oneembodiment the “N” image frames 246 are subsequently arranged to form a1×N wide area image of scene 210.

In the illustrated embodiment, controller 220 is configured to receive acontrol signal to control operation of components of image acquisitioncomponent 102. For instance, the control signal can include anactivation signal and/or information regarding operation of camera 204and/or scan mirror 209. Controller 220 is operably coupled to actuator222 and camera 204 and synchronizes the timing between the scan mirror209 and camera 204. In one embodiment, the controller 220 implements afield programmable gate array (FPGA) and/or includes calibrationinformation. For instance, to calibrate the scan angles (i.e., scanmirror 209 step size), a re-configurable look-up-table (LUT) is loadedinto a FPGA-based controller. The LUT maps the camera FOV 244 to theangular step size of the scan mirror 209 to limit overlapping data andgaps in the acquired image data for adjacent frames 246 of scene 210. Inone embodiment, for each successive cycle of scan mirror 209 throughscan range 240, image data received from a particular frame 246 (e.g.,Frame 1, Frame 2, Frame N) for each successive scan is received fromsubstantially the same spatial location within scene 210. In otherwords, each frame 246 of image data received at camera 204 for eachsuccessive cycle of scan mirror 209 defines substantially the samespatial boundaries within scene 210. Preferably, overlapping data orgaps in the image data is minimized.

Further, the LUT can be re-configured either automatically or based onuser entered parameters. For instance, in one embodiment the LUT isreconfigured automatically based on acquired image data. For example, ifimage processing determines that adjacent image frames 246 containoverlapping image data or significant gaps therebetween, the LUT can beautomatically adjusted to modify the angular position of scan mirror 209at the particular frame(s) to reduce the gaps and/or overlapping imagedata. In another embodiment, a user inspects the image data and, using agraphical user interface, makes manual adjustments to reduce the gapsand/or overlapping image data. In one embodiment, calibrationinformation is provided to controller 220 over a program interface. Forexample, controller software provided in processing component 104,described below, can include instructions for programming controller 220

Controller 220 sends a signal to actuator 222 to quickly “step” the scanmirror 209 between adjacent frames in approximately a few milliseconds.For example, the scan mirror 209 can have a 0.5 degree step responsetime of 1.5 ms. The controller 220 also sends a signal to the camera 204to cause the camera to acquire an optical image of the particular frame246 while scan mirror 209 “stares” at the particular frame. Preferably,controller 220 synchronizes the timing between the scan mirror 209 andcamera 204 such that there is limited image smear and ghosting in theacquired image data. In accordance with another embodiment, scan mirror209 is configured to pivot through scan range 240 using a continuousmotion. In other words, in this embodiment scan mirror 209 does not stopand “stare” at each frame 246. Instead, camera 204 is configured toacquire each frame 246 of image data as scan mirror 209 movescontinuously through scan range 240.

As discussed above, scan mirror 209 can be configured to pivot throughscan range 240 in successive and repeating cycles. For instance, whenscan mirror 209 reaches a boundary of the scan range 240, for examplescan mirror 209 is acquiring optical image data from frame “N”, the scanmirror 209 is configured to return to the first frame (i.e., “frame 1”)in scan range 240 to acquire another series of images from frames 243 ofscene 210. In another embodiment, the scan mirror 209 can be configuredto reverse direction to acquire image data from the plurality of frames246 in reverse order. Thus, image acquisition component 102 isconfigured to repeatedly acquire image data from frames 246 of scene 210in a back-and-forth pivoting manner. In one example, the image data foreach frame 246 is updated (i.e., additional image data is acquired forthe frame) one or more times a second resulting in a framing rate of 1Hz or greater. In another example, the framing rate is less than 1 Hz(i.e., image data is acquired for each frame 246 less than once persecond). As will be discussed below in greater detail, the series ofupdated image data for each frame 246 is provided to processingcomponent 104. In one example, the image data is utilized to generate avideo stream.

In accordance with one embodiment, scan mirror 209 directs optical image212 toward a stationary imaging lens 206 associated with camera 204. Theoptical image 212 is received through lens 206 and aperture stop 207along the optical axis 213. Camera 204 generates a digital datarepresentation of the optical image 212 which can be provided toprocessing component 104, illustrated in FIG. 1. In one embodiment, thelens 206 has a focal length of approximately 70-500 mm. Further, thelens can include a filter for blocking electromagnetic radiation havingparticular wavelengths. For example, the filter can be configured toblock at least a portion of UV light and/or light in the blue range ofthe visible light spectrum (i.e., wavelengths of 450-495 nm). Theaperture stop 207 is positioned between the lens 206 and image directingdevice 208 and is centered on the optical axis 212.

In the illustrated embodiment, components of image acquisition component102 are provided in an enclosure 248 configured to protect thecomponents from environmental elements. Enclosure 248 can include awindow 250 through which image data from scene 210 is acquired. Whilecontroller 220 is illustrated within enclosure 248, it is noted thatcontroller 220 can be provided external to enclosure 204. For instance,controller 220 can be remotely positioned from camera 204, such aswithin processing component 104.

FIGS. 3-7 illustrate embodiments of camera 204 and image directingdevice 208. As discussed above, image directing device 208 directsoptical images to camera 204 along an optical image path 214. Camera 204receives the optical images from the optical image path 214 along anoptical axis 213. Further, as discussed above, image directing device208 can include a single scan mirror 209 configured to pivot about anaxis. Further yet, image directing device 208 can include a plurality ofmirrors. For example, image directing device 208 can include a pluralityof scan mirrors 209 configured to pivot about one or more pivot axes.Further yet, the image-directing device 208 can also include one or morestationary mirrors.

In the embodiments illustrated in FIGS. 3 and 4, image directing device208 is configured to perform a one-dimensional scan of scene 210. Asillustrated in FIG. 3, camera 204 is focused on a portion of scan mirror209 and is configured to receive optical images along optical image axis213. Images of scene 210 are directed by scan mirror 209 along anoptical image path 214 to camera 204. In the illustrated embodiment,scan mirror 209 is configured to pivot about a single axis 330 that issubstantially perpendicular to optical axis 213 to minimize distortionof the reflected images. Scan mirror 209 pivots over a scan range ofless than 360 degrees. In one example, the scan range is less than 90degrees. Further, as illustrated in FIG. 3 axis 330 is substantiallyparallel to a light-reflecting surface 309 of mirror 209. In oneexample, axis 330 is substantially in the same plane as thelight-reflecting surface 309 of mirror 209. Camera 204 and lightdirecting device 208 can be positioned at ground level or,alternatively, above ground level. For example, camera 204 can bemounted on a support, such as a post, a distance above the ground. Inthe illustrated embodiment, scan mirror 209 is configured to pivot abouta substantially vertical axis 330. As such, camera 204 acquires imagesat a viewing angle that is substantially parallel to the ground (i.e.,perpendicular to the vertical axis 330). In another embodiment, axis 330can be oriented at an angle with respect to vertical. In this manner,camera 204 acquires images at a particular viewing angle with respect tothe ground.

Because pivot axis 330 is substantially perpendicular to optical axis213, frames of image data acquired from scene 210 are oriented in thesubstantially the same direction at all positions of scan mirror 209. Inother words, as scan mirror 208 pivots about axis 330 the orientation ofthe image frames does not rotate on a lens of camera 204.

In the embodiment illustrated in FIG. 4, camera 204 acquires image dataof a scene 210 that is oriented in a generally vertical direction. Inthis embodiment, scan mirror 209 is configured to pivot about a pivotaxis 340 that is substantially perpendicular to optical axis 213 todirect images to camera 204 along optical image path 214. As illustratedin FIG. 4, axis 340 is substantially parallel to a light-reflectingsurface 309 of mirror 209. In one example, axis 340 is substantially inthe same plane as the light-reflecting surface 309 of mirror 209 and isoriented in a horizontal, or substantially horizontal, direction.

In the embodiment illustrated in FIG. 5, image directing device 208 isconfigured to perform a multi-dimensional scan of scene 210. Asillustrated in FIG. 5, image directing device 208 includes a scan mirror209 configured to pivot about a first pivot axis 350 and a second pivotaxis 352. For instance, scan mirror 208 can be a 2-axis mirror. Pivotaxis 350 is illustratively similar to pivot axis 330 of FIG. 3. Further,in the illustrated embodiment second pivot axis 352 is substantiallyperpendicular with respect to first axis 350. Scan mirror 209 isconfigured to pivot about multiple axes 350 and 352 to acquire M×N imageframes from scene 210. While FIG. 5 illustrates a single, 2-axis scanmirror 209, it is noted that in other embodiments a plurality of scanmirrors can be utilized to perform a multi-dimensional scan of scene210. For example, in one embodiment two scan mirrors can be utilizedwherein a first scan mirror is configured to pivot about a first pivotaxis and a second scan mirror is configured to pivot about a secondpivot axis. Further, it is noted that in another embodiment amulti-dimensional scan can be performed of scene 210 using a single axismirror. For example, scan mirror 209 can be configured to pivot about asingle axis, such as axis 350. Further, camera 204 can be configured topan, or tilt, in a vertical direction. Tilting movement of camera 204and pivoting movement of scan mirror 209 can be controlled, and/orsynchronized with image acquisition of camera 204, using a controllersuch as controller 220.

In the embodiments illustrated in FIGS. 6 and 7, image directing device208 includes a plurality of mirrors utilized to acquire image data fromscene 210. In FIG. 6, image directing device 208 includes a scan mirror209 and a stationary mirror 369. Mirrors 209 and 369 direct image dataalong image path 214 to camera 204. Camera 204 receives the image datafrom path 214 along optical axis 213. Scan mirror 209 is configured topivot about pivot axis 360, to direct images of scene 210 to astationary mirror 369, which directs the images to camera 204. Asillustrated in FIG. 6, axis 360 is parallel to a light-reflectingsurface 309 of mirror 209. In one example, axis 360 is substantially inthe same plane as the light-reflecting surface 309 of mirror 209.Further, pivot axis 360 defines a plane that is perpendicular or,substantially perpendicular, to optical axis 213. As illustrated, axis360 is substantially vertical and axis 213 is substantially horizontal.

In FIG. 7, image directing device 208 includes a scan mirror 209 and astationary mirror 379. Mirrors 209 and 379 direct image data along imagepath 214 to camera 204. Camera 204 receives the image data from path 214along optical axis 213. Scan mirror 209 is configured to pivot aboutpivot axis 370 to direct light from frames of scene 210 to stationarymirror 379. In one embodiment, axis 370 is parallel to alight-reflecting surface 309 of mirror 209. For example, axis 370 can besubstantially in the same plane as the light-reflecting surface 309 ofmirror 209.

It is noted that the orientations of image directing device 208illustrated in FIGS. 3-7 are exemplary and are not intended to limit thescope of the concepts described herein.

In accordance with another embodiment, image acquisition component 102is configured to acquire images in environments having low light levels.For example, image acquisition component 102 can be configured toacquire images at night. As illustrated in FIG. 8, an illuminator 804 isprovided proximate camera 204 and is configured to provide light energyto enable camera 204 to obtain images of scene 210 in reduced lightlevels. Scan mirror 209 is configured to pivot about an axis 810 that issubstantially similar to axis 330 illustrated in FIG. 3. However, it isnoted that illuminator 804 and scan mirror 809 can also be utilized withthe embodiments of image directing device 208 illustrated in FIGS. 4-7.Illuminator 804 includes a scan mirror 809 that is illustrativelysimilar to scan mirror 209 and configured to pivot about an axis 812.

Scan mirror 809 can be synchronized with scan mirror 209 via a controlsignal. In this manner, illuminator 804 and camera 204 can be focused onthe same portion of scene 210 such that the illuminator 804 is activatedat substantially the same instance in time and on the same portion ofthe scene 210 as camera 204 acquires image data. Illuminator 804 isconfigured to transmit electromagnetic radiation includingelectromagnetic radiation having wavelengths in the visible lightspectrum, as well as infrared or near-infrared radiation, andultra-violet radiation, among others. In one embodiment, camera 204 is amultispectral and/or a hyperspectral imaging camera configured tosimultaneously acquire images at multiple wavelengths.

FIG. 9 illustrates one embodiment of processing component 104.Processing component 104 receives image data from image acquisitioncomponent 102 at an image acquisition module 902. The image datareceived by processing component 104 from the image acquisitioncomponent 102 can be either analog or digital. In one particularexample, the image data is communicated from image acquisition component102 using a communication protocol such as Camera Link, or the like.Further, as discussed above, the image data received by processingcomponent 104 can be data indicative of a video stream, a still image, aplurality of still images, among others.

Processing component 104 can include an analog-to-digital converterconfigured to receive an analog image data signal and output a digitalsignal representing the image. Further yet, component 104 can also beconfigured to compress the image data in real time using algorithms,such as, but not limited to, MPEG.

Image data acquisition module 902 can be configured to associate, witheach portion of image data received from image acquisition component102, spatial and/or time information. For example, module 902 can assigna time stamp to the image data indicative of a time at which the imagedata was acquired. Further, image data acquisition module 902 canassociate a positional identifier with each frame of image data. Forexample, a positional identifier indicates an angular position of thescan mirror when the image data was acquired. In one embodiment, acounter is implemented that increments for each frame of image datareceived. The counter can be utilized to associate a frame number (e.g.,N=1, N=2. . . N=80) to the acquired image data. It is noted that inother embodiments, image acquisition component 102 can be configured toprovide spatial and/or time identifier information with the image data.For example, image acquisition component 102 can provide data such as aframe number or angular position of the scan mirror when the image datawas acquired. Further, a time stamp can be provided with the image data.In one embodiment, a compass or global positioning system (GPS) receivercan be utilized to provide positional information with the image data.

Processing component 104 also includes an image processing module 903configured to autostitch the plurality of frames of image data receivedby module 902 to form a wide area image. For example, module 903 canutilize positional information (such as frame number, etc.) to stitchthe frames of image data. Module 903 can further be configured to removeoverlapping image data and/or gaps from adjacent frames of image data.

Image processing module 903 also contains dedicated algorithms forperforming target classification and change detection. Targetclassification contains processing logic to classify particular pointsor items of interest from the image data. For example, targetclassification can be configured to identify an unknown object as aperson, a vehicle, an animal, to name a few, from the digital datarepresentation of the acquired image.

Additionally, change detection is provided in module 903 and performsimage registration and detects scene changes. Change detection can beperformed by registering a frame, or frames, of image data and comparingsuccessive frames of image data to each other. A number of testingprocedures can be utilized to perform the change detection operations.For example, linear independence tests, vectorized tests, or edge motiontests can be utilized. Further, the change detection can be performed byutilizing application specific information such as region of interest orknown sizes or shapes. In one embodiment, a Wronskian vector changedetection algorithm is utilized. In this manner, a vector method isutilized that determines change at each image pixel (with respect to areference image) based on a calculation using the test pixel andsurrounding pixels in a square region (i.e., 3×3, 5×5, 7×7). In anotherembodiment, the spatial resolution of the change detection algorithm(the size of the square region) is utilized.

In one embodiment, change detection is performed on a plurality offrames of image data simultaneously. For instance, image processingmodule 903 receives a plurality of image data from frames 246 of scene210. Image processing module 903 registers each frame of image data toprovide a reference for performing change detection. Additional imagedata is acquired from frames 246 of scene 210 during subsequent cyclesof scan mirror 209 through scan range 240. The additional image datafrom the frames are provided to image processing module 903. Imageprocessing module 903 compares the image data to the registered imagedata to detect changes. In one embodiment, module 903 detects changes ineach of the plurality of image frames on a continuous basis.

The image data can be supplemented or annotated based on detectedchanges. For example, the image processing module 903 can supplement theimage data with a visual indicator (e.g., highlighting the area of theimage data including the detected change). Further, an audible indicatorcan be provided such as an alarm or indictor light to indicate that achange in the image data has been detected. A detected change caninclude an unknown object as a person, a vehicle, an animal, to name afew, identified from the digital data representation of the acquiredimage.

Processing component 104 can include controller software 904 to programcontroller 220 of image acquisition component 102 used to controloperation of the camera 204 and scan mirror 209 of image acquisitioncomponent 102. For instance, the controller software 904 can be used toprogram the synchronization and step size of the scan mirror 209. In oneembodiment, processing component 104 sends a signal to an FPGAassociated with controller 220 to re-configure an LUT containing mappinginformation of the camera 204 and scan mirror 209. It is noted that someof the processing functions illustrated within component 104 can beprovided with image acquisition component 102 (for instance, withinenclosure 248).

In one embodiment, processing component 104 is employed by a hostcomputer and includes a user interface 914. A user utilizes theinterface 914 to input control parameters. For instance, a user candefine parameters such as scan rate, step size, scan range, etc. In oneembodiment, a user inspects the autostitched image and, using agraphical user interface, provides a user input to reconfigure the scanmirror step size. For instance, a user can modify the number of framesacquired from scene 210 or modify the field-of-view for each frame 246.The user input can be utilized to reconfigure controller 220 forcontrolling camera 204 and image directing device 208.

The user interface 914 can provide a visual user interface for displayof operating parameters and image data. For example, user interface 914can provide a visual output from image processing module 903. A monitorcan be provided to display an indication that a point or item ofinterest has been detected, such as a person, automobile, boat,airplane, animal, etc. The user can adjust parameters (i.e.,sensitivity, range, points of interest) through interface 914.

The image data can be provided to a storage component, such as storagecomponent 106 illustrated in FIG. 1. The stored image data can include aplurality of image frames stored as separate data files. In anotherembodiment, the autostitched image provided by image processing module903 is stored in the storage component.

The image data can be provided to the storage component in compressedstate to reduce the required memory for storing the image data. In oneembodiment, the image data includes position and/or time stampinformation associated with the image data stored in storage component106. Processing component 104 can further be configured to retrieve andprocess archived image data from the storage component 106. For example,the image data can be retrieved using the position and/or time stampinformation associated with the stored image data. In this manner, datacan be retrieved from the storage component 106 based on the time atwhich the image data was acquired and/or the spatial position of theimage data (e.g., a frame number).

In accordance with another embodiment, the processed image data isprovided to a display component, such as display component 108illustrated in FIG. 1. FIG. 10 illustrates one embodiment of displaycomponent 108. In the illustrated embodiment, display component 108includes a processor 1002 configured to receive image data and providethe image data to a display device 1008 configured to visually renderthe image data.

In accordance with one embodiment, display software 1004 providesfurther processing of the image data. For instance, the software 1004can analyze the image data and remove overlapping data and/or gapsbetween adjacent frames. Further, software 1004 implemented on processor1002 utilizes positional information provided with portions of the imagedata (i.e., frame) to arrange the image data on display 1008.

Further, a brightness and/or contrast of the image data can be adjustedby modifying a camera exposure time and/or using a histogramequalization. Adjustment of the brightness and/or contrast can beperformed either manually (i.e., a user enters parameters to control thecamera exposure time) or automatically (i.e., a processing componentadjusts the camera exposure time based on observed brightness and/orcontrast).

The processor 1002 displays the image data simultaneously on multipledisplays 1010. For example, the image data can be rendered on aframe-by-frame basis to a plurality of monitors wherein one or moreframes of image data are displayed on a separate monitor. Asillustrated, eight (8) monitors 1010 are arranged in a semicircle suchthat the plurality of monitors “wrap” around a user to maintain aconstant viewing distance between the user and each of monitors 1010.However, any number of monitors can be utilized to display the imagedata. For example, in one embodiment eighty (80) monitors 1010 can beutilized.

Processor 1002 can be implemented on a computer having multiple outputs(for example, multiple PCI express slots). In this manner, multipledisplays (i.e., multiple monitors) can be driven by a single computer toenable enhanced synchronization of the multiple displays.

As described above, image acquisition device 102 is configured toacquire image data over successive and repeating cycles of scan mirror209 of scene 210. The image data acquired from the successive scans isprovided to display component 108, and is frequently updated based onthe framing rate at which the successive scans of image data areacquired. For instance, image acquisition component 102 acquires imagedata across scan range 240 one or more times per second. The image datacan be provided in real-time to display component 108. In this manner,the images displayed on display device 1008 can be refreshed severaltimes per second. Further, the processor 1002 is configured to displayimage data from the successive scans of scene 210 (e.g., Frame 1, Frame2, Frame 3, etc.) in a stationary, or substantially stationary positionon display device 708. For instance, additional image data acquired fromscene 210 during the successive scans is provided to display device 1008such that each frame of image data (i.e., frame 1, frame 2, frame N,etc.) is provided in a similar position and orientation on displaydevice 1008. In this manner, the displayed image data of scene 210 doesnot have the appearance of “scrolling” across display 1008.

Further, in one embodiment display 1008 is configured to visually renderthe detected changes in the image data. For instance, processor 1002 canbe configured to visually render to display 1008 an indication of adetected change, such as a mark or highlighted indication. For example,a visual mark or identifier can be utilized to overlay a detected changein the image data. Further, an audible indication such as an audiblealarm can be provided to indicate that a change has been detected. Thevisual and/or audio indication can indicate the presence of an unknownobject such as a person, a vehicle, an animal, or the identification ofan object of interest, such as a vehicle or person of interest in theimage data.

It is to be understood that even though numerous characteristics andadvantages of various embodiments of the invention have been set forthin the foregoing description, together with details of the structure andfunction of various embodiments of the invention, this disclosure isillustrative only, and changes may be made in detail, especially inmatters of structure and arrangement of parts within the principles ofthe present invention to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed. Forexample, the particular elements may vary depending on the particularapplication for the recording medium while maintaining substantially thesame functionality without departing from the scope and spirit of thepresent invention.

1. An image acquisition system for capturing images of scenes, thesystem comprising: a stationary image acquisition device that receivesoptical images; and a light-directing device that pivots about a pivotaxis and directs scene images to the image acquisition device, whereinthe light-directing device pivots over a scan range that is less than360 degrees, wherein the light-directing device is a scan mirror, andwherein the pivot axis of the scan mirror is substantially parallel to alight-reflecting surface of the scan mirror.
 2. The image acquisitionsystem of claim 1, wherein the image acquisition device is configured toreceive optical images along an optical axis and the light-directingdevice is configured to direct scene images toward the image acquisitiondevice along an optical path, and wherein the pivot axis of thelight-directing device defines a plane that is substantiallyperpendicular to the optical axis.
 3. The image acquisition system ofclaim 1, wherein the light-directing device is configured to directscene images toward the image acquisition device along an optical axisof the image acquisition device, and wherein the pivot axis of thelight-directing device is substantially perpendicular to the opticalaxis.
 4. The image acquisition system of claim 3, wherein a first scanrange boundary defines a first rotational limit of the light-directingdevice and a second scan range boundary defines a second rotationallimit of the light-directing device, wherein the light-directing deviceis configured to pivot in a predetermined path between the first andsecond scan range boundaries in repeating cycles.
 5. The imageacquisition system of claim 4, wherein the light-directing device pivotsabout the pivot axis over a scan range that is less than 90 degrees. 6.The image acquisition system of claim 5, wherein the pivot axis of thelight-directing device is substantially vertical.
 7. The imageacquisition system of claim 5, wherein the pivot axis of thelight-directing device is oriented at an angle relative to vertical. 8.The image acquisition system of claim 3, wherein the pivot axis of thelight-directing device is a first pivot axis, and whereinlight-directing device is configured to pivot about a second pivot axisthat is substantially perpendicular to the first pivot axis.
 9. Thesystem of claim 3, and further comprising an illuminator configured totransmit light energy to illuminate a scene, and wherein the imageacquisition device is responsive to the transmitted light energy. 10.The system of claim 3, wherein the image acquisition device includes atleast one of a multispectral and hyperspectral imaging camera configuredto simultaneously acquire images at multiple wavelengths.
 11. The imageacquisition system of claim 3, and further comprising: an actuatoroperably coupled to the light-directing device, wherein the actuator isconfigured to pivot the light-directing device about the pivot axisbetween a plurality of angular positions; and a controller configured tocontrol operation of the actuator to pivot the light-directing device toa selected one of the plurality of angular positions, wherein thecontroller is further configured to control the image acquisition deviceto acquire an optical image from the optical axis when thelight-directing device is at the selected one of the plurality ofangular positions.
 12. The system of claim 11, wherein the controllerincludes synchronization information that maps the plurality of angularpositions of the light-directing device to a field of view of the imageacquisition device.
 13. An image acquisition system for capturing imagesof a scene, the system comprising: an image acquisition device thatreceives scene images along an optical image path and generates adigital data representation of the optical images; and a light-directingdevice that directs optical images toward a stationary imaging lensassociated with the image acquisition device, wherein thelight-directing device pivots about a pivot axis over a plurality ofangular positions that collectively define a scan range, and wherein thelight-directing device is oriented such that optical images received bythe image acquisition device are generally oriented in the samedirection at each angular position throughout the scan range.
 14. Theimage acquisition system of claim 13, wherein the light-directing devicepivots over the plurality of angular positions in a predetermined pathin repeating cycles, and wherein the image acquisition device issubstantially stationary with respect to the scene.
 15. The imageacquisition system of claim 14, wherein the image acquisition device isconfigured to receive optical images along an optical axis, and whereinthe pivot axis of the light-directing device is substantiallyperpendicular to the optical axis.
 16. The image acquisition system ofclaim 14, wherein the light directing device is a mirror having a lightreflecting surface, and wherein the pivot axis of the mirror issubstantially parallel to the light reflecting surface.
 17. A method ofacquiring scene images, comprising: providing an image acquisitiondevice; providing a light-directing device that directs images of ascene toward the image acquisition device; pivoting the light-directingdevice about a pivot axis between a plurality of angular positions,wherein pivoting comprises pivoting the light-directing device inrepeating cycles over an angular scan range that is less than 90degrees; acquiring, at the image acquisition device, a plurality ofimage frames at the plurality of angular positions; and rendering theacquired plurality of image frames to a display device, whereinrendering includes generating an image stream of the scene from theimage data acquired at each of the plurality of angular positions. 18.The method of claim 17, wherein pivoting comprises: pivoting thelight-directing device back-and-forth between a first limit of the scanrange and a second limit of the scan range.
 19. The method of claim 18,and further comprising: acquiring, at the image acquisition device,additional image data for each of the plurality of angular positionsduring the repeating cycles; and rendering the additional image data foreach of the plurality of angular positions to the display device suchthat the rendered image data represents an image stream of the scene.20. The method of claim 18, and further comprising: acquiring a firstportion of image data for each of the plurality of angular positionsduring a first cycle of the repeating cycles; acquiring a second portionof image data for each of the plurality of angular positions during asecond cycle of the repeating cycles; and performing change detection onthe second portion of image data for each of the plurality of angularpositions to identifying changes in the image data.